1. Field of the Invention
The present invention relates to processes and apparatuses for treating drilling fluids for fossil fuel wells.
2. Brief Description of the Prior Art
During the process of drilling for fossil fuels, the rock formations that are being penetrated by the drilling bit creates drilled cuttings which, to varying degrees and amounts, eventually disintegrate into smaller drilled cuttings, referred to as drilled solids that become an undesirable component of such water phase continuous (“WBM”), or hydrocarbon phase continuous drilling fluids and which convey the drilled cuttings to the surface of the earth and where they are removed, to varying degrees and amounts by one or more types of cuttings and solids removal equipment.
Additionally, in order to contain the fluids within the formations being drilled, it is often necessary to supplement the drilling fluid with weighting agents such as barite, hematite, galena, calcium carbonate, etc., which are similar in size to the drilled solids and for which the specific gravity of said weighting agents is approximately equal to, or greater than the specific gravity of the drilled solids. Because the drilled solids are undesirable and they are small in size, to varying degrees of success, they are commonly removed from the drilling fluid using a decanting centrifuge.
For WBMs, a solids removal process, commonly referred to as “stripping” or “dewatering”, or “enhanced centrifuging”, is used to enhance the removal of both the water-wet drilled solids and water-wet weighting agents to varying degrees using a decanting centrifuge's principle of solid-liquid separation. However, for an hydrocarbon phase continuous drilling fluid in which the water phase is discontinuous and for which the solid phase is purposely oil wet to maintain such drilling fluid's rheological properties and to prevent such drilling fluid's water phase from becoming the continuous phase (a phenomenon commonly referred to as “flipping”), such a process has not been successfully developed. In some prior processes for removal of solids from hydrocarbon phase continuous drilling fluids employ coagulants and flocculants are used to contact the particulate matter directly without being dissolved a priori. In other prior art processes from the removal of solids from hydrocarbon phase continuous drilling fluids the wettability of the particulate matter is altered from being oil wet to being water wet before the particulate is contacted by any coagulants or flocculants. However, there is a continuing need for a process for the efficient removal of solids from hydrocarbon phase continuous drilling fluids.